Al2O3- and TiO2-pillared montmorillonites modified with Cu or Co were studied as catalysts of NO reduction with ammonia. Transition metals were introduced to pillared clays (PILCs) by ion exchange method or simultaneously with pillaring agent to the parent montmorillonite. The obtained materials were characterized using: XRF (composition), XRD (structure), BET and Horvath and Kawazoe (H-K) (texture) and NH3-TPD (acid centres). The clays intercalated with titania are significantly more active than alumina pillared ones. TiO2-intercalated montmorillonites modified with Cu have been found to be the most active catalysts in SCR of NO with ammonia in the low temperature region (250-450degreesC), while Co-containing clays are much better at high temperatures (T > 400 degreesC). (C) 2003 Elsevier Science B.V. All rights reserved.